There are known patents of the Russian Federation No 22059188 of 27 Apr. 1999, No 22150651 of 10 Jun. 2000, No 22239760 of 10 Nov. 2004, which provide torsion of the launched projectile (an arrow or a bullet) around the longitudinal axis for stabilization of an arrow during the flight. However, each of the said crossbows has an intricate and heavy moving unit dedicated for the spinning of an arrow or a bullet, hence requires increased demanded bow force, its weight and the weight of the crossbow on the whole.
Also there is known a sport crossbow patent of the Russian Federation No 22308655 of 20 Oct. 2007 (herein below called ‘prototype’), which comprises a bow, a shoulder stock, a trigger, a stock and a slide, an arrow of which is made hollow; the stock is made in the shape of a tube, outside diameter of which is smaller than an inside diameter of an arrow, a slide is made in the shape of a ring with its inside diameter bigger than an outside diameter of the stock and smaller than an outside diameter of an arrow, moreover there is a groove on the slide for the bow string, and the bow string in its central part is split. This crossbow can contain two diametrically opposed helical grooves on the external surface of the tube-stock and at the same time on the internal surface of the arrow tailpiece there are two diametrically opposed pins responding to the grooves.
The disadvantages of this crossbow are first of all comparatively large radial dimensions of an arrow which encloses a tubular stock and its enlarged length, required for interaction with annular slide and enabling sufficient duration of pins contact at the tailpiece of the arrow with the helical grooves of the stock. For the acceleration of such an arrow with enlarged dimensions and in order to overcome friction forces created by its rotation related to the slide and stock it is required corresponding effort of bow string tensioning, ensured by provision of required rigidity (thickness of limbs) of the bow, therefore its increased dimensions and weight and consequently of the crossbow on the whole. Second of all, the necessity to make a split bow string complicates the design of the crossbow.